My DIY temp control

StangMan

This is only my second post here but I wanted to share my progress. 

After attempting my first overnight cook of some pork butt. I woke up at 5am to find my temp down to 150F. It turned out okay,but it was a little drier then I would have liked. 

When I looked into buying a temperature control unit. I about choked at the prices. So I did a little research and decided to make my own. 


I'm thinking of doing a brisket for my 1st cook with it, wish me luck ;-)

Cookbook_Chip

So cool!  Okay, how much did you spend in parts?  

lousubcap

Welcome aboard and enjoy the journey. 
Great DIY right there-way beyond my skill-set.  You may want to give it a test run before heading down the brisket road.  FWIW-

GoooDawgs

Wow!  Is that for time travel too? 

StangMan

Cookbook_Chip said:

So cool!  Okay, how much did you spend in parts?  

I have about $40 in it so far.

lousubcap said:

Welcome aboard and enjoy the journey. 
Great DIY right there-way beyond my skill-set.  You may want to give it a test run before heading down the brisket road.  FWIW-

Thanks, I'm a machinist by trade so I have access to fancy machines like CNC lasers. I've been going back and forth between doing a brisket or throwing in a cheep pork butt. I'll probably chicken out last minute and do pork for my 1st cook with this thing.

GoooDawgs said:

Wow!  Is that for time travel too? 

Ha...how did you know. I'm building the flux capacitor attachment for it now!

HeavyG

Cool project!

Those little PID controllers are pretty slick. Real easy to use to make your own sous vide setup or use in home brewing also.

Those PID controllers can run from $10-$30ish. Looks to me that he did his own case from sheet (well done!). Some toggle switches and AC plug connector... I'll guess the parts cost was in the neighborhood of... $50? 

StangMan

HeavyG said:

Cool project!

Those little PID controllers are pretty slick. Real easy to use to make your own sous vide setup or use in home brewing also.

Those PID controllers can run from $10-$30ish. Looks to me that he did his own case from sheet (well done!). Some toggle switches and AC plug connector... I'll guess the parts cost was in the neighborhood of... $50? 

You nailed it. I picked up the contoller and switches from amazon for about $40. That plug socket cost more then the controller...go figure.

SemolinaPilchard

I see a possible budding sideline business in the making. Great work. Very impressive.

lkapigian

Great job, but I would want to know why your pit got down to 150 in the first place, without knowing that you may even have a problem with a controller...very cool though

Legume

lkapigian said:

Great job, but I would want to know why your pit got down to 150 in the first place, without knowing that you may even have a problem with a controller...very cool though

Didn't use center cut lump.

NPHuskerFL

Nice control work. Are the nuts on the backside going to clear to seal up to the lower vent?

Toxarch

Looks nice. Did you put some kind of one way valve after the fan? If not, the natural draft will draw in too much air and you will blow right by your target temp.

c_sloan

PLLLLEEEAAASE call it a brisket flux capacitor! Very cool!

StangMan

NPHuskerFL said:

Nice control work. Are the nuts on the backside going to clear to seal up to the lower vent?

The blower fits in well, I need to run to the hardware store and pick up some random nuts and bolts and a pop rivet gun. So I can clean it up some.

StangMan

Toxarch said:

Looks nice. Did you put some kind of one way valve after the fan? If not, the natural draft will draw in too much air and you will blow right by your target temp.

I do not. I thought about it but the DigiQ one uses the same blower and they don't use a damper. I'm sure I'll have a few revisions before I get it right.

kl8ton

Dang it. . . flux capacitor comments taken. . . let's see. . . 

A safe cook to practice with. . . an overnight water boil?  With pecan wood?

Toxarch

StangMan said:

Toxarch said:

Looks nice. Did you put some kind of one way valve after the fan? If not, the natural draft will draw in too much air and you will blow right by your target temp.

I do not. I thought about it but the DigiQ one uses the same blower and they don't use a damper. I'm sure I'll have a few revisions before I get it right.

My Stoker blower does have a metal flapper to stop any draft. I mention it because when it gets dirty, it will stick open and the Temp will rise. This valve is a very simple design.

Toxarch

kl8ton said:

Dang it. . . flux capacitor comments taken. . . let's see. . . 

A safe cook to practice with. . . an overnight water boil?  With pecan wood?

How about: That money you saved building it is going straight to the electric bill. 1.21 gigawatts is a lot of electricity for 1 brisket cook.

SmokeyPitt

Nice!  I am using a cheap controller as well.  Your enclosure might look a little better than mine.  

StangMan

SmokeyPitt said:

Nice!  I am using a cheap controller as well.  Your enclosure might look a little better than mine.  

Hay man that's cool. The important thing is that it works. 

I do have quick question for you. Do you have the blower connected directly to the controller? The unit I have came with a solid state relay. I have the ability to supply a separate 12V source,to the SSR, but it would be easier to power the blower straight off the controller.

SmokeyPitt

StangMan said:

SmokeyPitt said:

Nice!  I am using a cheap controller as well.  Your enclosure might look a little better than mine.  

Hay man that's cool. The important thing is that it works. 

I do have quick question for you. Do you have the blower connected directly to the controller? The unit I have came with a solid state relay. I have the ability to supply a separate 12V source,to the SSR, but it would be easier to power the blower straight off the controller.

The fan I am using is DC powered so I used a DC power supply that is connected to the relay on the controller. It would probably be better to use an SSR because it will isolate it from the controller.

StangMan

SmokeyPitt said:

StangMan said:

SmokeyPitt said:

Nice!  I am using a cheap controller as well.  Your enclosure might look a little better than mine.  

Hay man that's cool. The important thing is that it works. 

I do have quick question for you. Do you have the blower connected directly to the controller? The unit I have came with a solid state relay. I have the ability to supply a separate 12V source,to the SSR, but it would be easier to power the blower straight off the controller.

The fan I am using is DC powered so I used a DC power supply that is connected to the relay on the controller. It would probably be better to use an SSR because it will isolate it from the controller.

That's what I thought. I'll probably wire in the SSR just to be safe. Thanks for your help.

BilZol

Cool project. I thought about going that route myself, I just lacked the talent and knowledge. Priceless. 
Resl clean looking set up. You should know pretty quickly if it's going to set and hold your temp. 

Photo Egg

StangMan said:

Toxarch said:

Looks nice. Did you put some kind of one way valve after the fan? If not, the natural draft will draw in too much air and you will blow right by your target temp.

I do not. I thought about it but the DigiQ one uses the same blower and they don't use a damper. I'm sure I'll have a few revisions before I get it right.

My BBQ Guru DigiQ does have a slide damper. Depending on desired cooking temp it can be slid open or closed to adjust natural draft when the fan is not running. Thought all their models had this feature.

Botch

Welcome, and fantastic first post and controller!  
Pic of your 'stang, please; I'm assuming that's where your handle comes from.  

blasting

@StangMan   Welcome aboard.  Very strong first post.

As handy as I may be in other areas, I'm dumb  as a brick when it comes to electronics.  I'm super impressed - please keep us posted with your project.

StangMan

Photo Egg said:

StangMan said:

Toxarch said:

Looks nice. Did you put some kind of one way valve after the fan? If not, the natural draft will draw in too much air and you will blow right by your target temp.

I do not. I thought about it but the DigiQ one uses the same blower and they don't use a damper. I'm sure I'll have a few revisions before I get it right.

My BBQ Guru DigiQ does have a slide damper. Depending on desired cooking temp it can be slid open or closed to adjust natural draft when the fan is not running. Thought all their models had this feature.

oh, that makes sense. That should be an easy enough fix. I can add a slider on the intake side of blower. Thanks!

StangMan

Botch said:

Welcome, and fantastic first post and controller!  
Pic of your 'stang, please; I'm assuming that's where your handle comes from.  

I wish I still did. I've had a couple of mustangs over the years but once the family came along my wife "suggested" a more practical mode of transportation.

So now instead of tinkering with my cars I smoke meats....

GregW

Nice work.
I probably would do a dry run with a pot of water in the egg to see how it performs.
Are you planning to use PID control or PI?
From my experience PID can be temperamental to setup.
I know some of these controllers have a self-tuning PID loop setup. The controller's I use for other purposes do not, and they are difficult to get PID to control correctly.
Hopefully the self-tuning loop feature will work well for the egg.

HeavyG

GregW said:

Nice work.
I probably would do a dry run with a pot of water in the egg to see how it performs.
Are you planning to use PID control or PI?
From my experience PID can be temperamental to setup.
I know some of these controllers have a self-tuning PID loop setup. The controller's I use for other purposes do not, and they are difficult to get PID to control correctly.
Hopefully the self-tuning loop feature will work well for the egg.

I'm not familiar with the OP's specific controller but for this purpose you don't really need to bother with it trying to learn or keep a tight specific temp.

The ones I've used you can set a tolerance - say a few degrees above or below your set temp and just let the average temp be about where you want it.

It's cool that the bigger dollar pit controllers can hold a temp within a degree or two but that is just not really necessary. Hell, my Karubecue cycles in a range of about 15°F above/below my desired temp and that has zero impact on the finished product.

SmokeyPitt

GregW said:

Nice work.
I probably would do a dry run with a pot of water in the egg to see how it performs.
Are you planning to use PID control or PI?
From my experience PID can be temperamental to setup.
I know some of these controllers have a self-tuning PID loop setup. The controller's I use for other purposes do not, and they are difficult to get PID to control correctly.
Hopefully the self-tuning loop feature will work well for the egg.

My controller has an auto-tune feature and I keep that enabled and it does a fine job. I find it helps if you get the temp in the ballpark first. I see "AT" indicator on @StangMan 's controller so I think that is the auto-tune indicator.